Mechanical Properties of HTPB Propellant under Shear Loading at Low Temperature

A new type of shear loading fixture and tensile testing machine with a refrigeration system was utilized to conduct Hydroxyl-terminated polybutadiene (HTPB) propellant low strain rate (0.01 similar to 1.00 s(-1)) shear loading tests at low temperature (223 K similar to 298 K). The shear strength and shear modulus of the HTPB propellant under different loading conditions were studied, and the master curves of the shear mechanical properties were constructed. It is found that the shear strength of HTPB propellant increases with increasing of shear strain rate and decreasing of temperature. The change of shear strength with temperature and strain rate conforms to the linear double logarithmic relationship. The initial shear modulus has a good linear double logarithmic relationship with the strain rate but changes nonlinearly with the logarithmic temperature. The shift factor of HTPB propellant shear strength and initial shear modulus changes exponentially with temperature after taking logarithm. The master curve of the initial shear modulus of HTPB propellant shows an "S"-shaped change trend, and a linear equation is used to fit the master curve of shear strength to obtain a better fitting effect.